This proposal investigates the molecular basis of information flow in cancer cells. The proposed Northwestern University Physical Sciences-Oncology (NU-PSOC) program is organized along a hierarchy of structure and function and consists of five projects areas, each focused on different aspects of the storage and expression of genetic information. Each project integrates methods and ideas of experimental molecular and cell biology with experimental methods and theoretical ideas from the physical sciences to achieve a quantitative and predictive understanding of fundamental mechanisms and principles in the regulation and expression of genes, in normal health and development, and in cancer.